Train from Zurich to Munich

That is a great and a a great option, with one caveat--- how much time are you leaving between landing at the airport and the train departure? If your plane is late and you miss that train, you may lose the ticket---it is non-refundable. I don't know if itis changeable, but I doubt it. Check the conditions of that type of ticket.

You should definitely NOT NOT NOT rent a car to drive from Zurich to Munich. You should also never make concrete travel plans on the day your flight lands in Europe.

sdk,

As previously mentioned, DO NOT rent a car for that trip. Driving after a long international flight in a jet lagged state has been compared to driving in an impaired condition. There are some other caveats to be aware of, such as having the highway tax vignette if your route takes you through Austria (hefty fines for those caught without it).

It would help to know what time your flight lands? There are a few direct trains from Zürich airport to Munich every day, and many others with changes. For example, there's a direct departure at 13:21, arriving Munich Hbf at 17:28 (time 4H:07M, reservations compulsory). One benefit of taking the train is that you'll either be able to enjoy the scenery or have a short power nap.

While you could buy advance tickets for the train, most of us here on the forum don't recommend that. The fast trains usually have compulsory seat reservations which are specific to a particular train, date and departure time. If you miss the train you've booked for any reason (such as flight delays or whatever), your tickets won't be usable and you'll have to stand in a possibly long queue at a ticket office to deal with that. The end result is that you'll end up paying more, either for a change fee or an entirely new ticket. The easiest solution is simply to buy your tickets at the Zürich airport station. Note that there are separate ticket offices for local trains and international trains (which is the one you'll be using).

It would be a gamble to purchase Sparpreis tickets from Zurich airport to Munich. It might be a good gamble depending on your appetite for risk. As was stated, if you miss your train, you will need to buy full fare tickets for the next one. I'll use the prices in CHF from the SBB site, which are closely equivalent to the prices in Euro.
Sparpreis tickets are 95 CHF for 3 adults, 2nd class. To get this price, you will need to buy on-line 3 months before your travel date. Since there are a limited number of tickets offered at this low price, they will raise quickly (a few days) after they go on sale after they get bought up. Then only higher priced tickets will be available, probably about 160 CHF.
Standard price tickets, bought on arrival, will be 270 CHF.

So here is the bet, assuming you leave a few hours for flight delays before your departure time.
Purchase the Sparpreis tickets for 95 CHF, your plane is on time (or close), you win.
Your plane experiences a substantial delay, purchase another set of tickets at 270 CHF, so your outlays is 365 CHF, you lose.
Just buy tickets after you arrive, pay 270 CHF no matter what.

So if your flight is on time (or close) 35% of the time, you will come out ahead in the long run (95/270=0.35)

I've done this several times and won each bet, but I guess some day I may come up a loser. This is what gambling is all about. Just know the consequences of the bet going in. You may want to weigh that versus the cost of flying directly into Munich.

Thanks everyone for the input! I am kind of leaning towards the gamble since I could save quite a bit.

Steve